Create a Bootstrap Starter Theme in Eleventy

With the rise in the JAMStack way of thinking, there has been a lot of development in static site generators. One that is quickly gaining popularity is Eleventy. Eleventy is very similar to Jekyll, but compiles much faster because it’s built on Node. What makes Eleventy stand out is its simplicity and flexibility.

Eleventy was created to be a JavaScript alternative to Jekyll. It’s zero-config by default but has flexible configuration options. Eleventy works with your project’s existing directory structure.

Eleventy uses independent template engines. We don’t want to hold your content hostage. If you decide to use something else later, having your content decoupled in this way will make migration easier

In this tutorial I’m going to show you how to quickly set up a boilerplate Eleventy theme using Bootstrap as our CSS framework and Parcel as our bundler. The goal of this tutorial isn’t to build a fully themed website, but rather to create a simple boilerplate. The only assumption it makes is that you want to use Eleventy and Bootstrap.

Below is what we’ll create.

eleventy bootstrap starter themeClick to expand

1. Initialize The Project and Install the Dependencies

  1. Open up a new terminal window and run npm init in a new directory . Follow the prompts and enter your info. In my case I ran npm init in a directory named eleventy-bootstrap-starter-demo. I just used the default values.

      "name": "eleventy-bootstrap-starter-demo",
      "version": "1.0.0",
      "description": "",
      "main": "index.js",
      "scripts": {
        "test": "echo \"Error: no test specified\" && exit 1"
      "author": "",
      "license": "ISC"
  2. Install development dependencies by running npm i @11ty/eleventy npm-run-all -D.
  3. Install Parcel by running npm install -g parcel-bundler.

    • I chose Parcel because it’s a Blazing fast, zero configuration web application bundler. Essentially, it will bundle and compile our js and scss by default.
  4. Install project dependencies by running npm i bootstrap jquery popper.js

Now that we have our dependencies installed, we can start building out our boilerplate theme. A good place to start is the header and footer partials, since these will be shared across all page templates.

  1. In the root of your project, run the follow commands to create a blank header and footer partial. Note that it’s Eleventy Convention to put your partials in a _includes directory.

    mkdir _includes
    mkdir _includes/shared
    touch _includes/shared/footer.njk
    touch _includes/shared/header.njk
  2. Create a data file to store site variables at ` _data/site.json by running the following commands. Note that it's [Eleventy Convention]( to store site variables in a _data directory. In our case we're adding default title and description` values to be loaded in the meta data of our site.

mkdir _data
touch _data/site.json
  "title": "Add the title of your website here. This is used in the <title></title>",
  "description": "Add your site description here. This is used in <meta name='description' content=''>"

3. Import Bootstrap

Now that we have a base, we can import Bootstrap as our framework of choice. Since we will be using Parcel as our bundler, we’re going to follow Parcel’s Bootstrap recipe.

  1. In order to keep our assets organized, run the following commands in the root of your project to create the correct file structure.

    mkdir _assets
    mkdir _assets/css
    mkdir _assets/css/vendor
    touch _assets/css/vendor/_bootstrap.scss
  2. Add the following to _assets/css/vendor/_bootstrap.scss

    @import "./../../../node_modules/bootstrap/scss/bootstrap.scss";
  3. In order to override Bootstrap’s default variables, run the following commands in the root of your project to create a _bootstrap_overrides.scss file. This is where you can override the default variables.

    mkdir _assets/css/base
    touch _assets/css/base/_bootstrap_overrides.scss
  4. As a note, I added the following to _assets/css/base/_bootstrap_overrides.scss

    // Override Bootstraps Variables Here
    // Reference node_modules/bootstrap/scss/_variables.scss for a full list of variables
  5. Now that we have Bootstrap and our custom overrides file created, open up _assets/css/main.scss and import the files.

    // Bootstrap Overrides
    @import "./base/bootstrap_overrides";
    // Bootstrap
    @import "./vendor/bootstrap";
  6. In order to load Bootstrap’s Popovers and Tooltips dependencies, run the following commands in the root of your project.

    mkdir _assets/js
    mkdir _assets/js/vendor
    touch _assets/js/vendor/popover.js
    touch _assets/js/vendor/tooltip.js
    touch _assets/css/main.scss
  7. Open _assets/js/vendor/popover.js and add the following. This enables popovers everywhere.

    import $ from "jquery";
    $(function () {
  8. Open _assets/js/vendor/tooltip.js and add the following. This enables tooltips everywhere.

    import $ from "jquery";
    $(function () {
  9. Now we need to import all of our js and scss in to one file for Parcel to bundle. In the root of your project run touch _assets/js/main.js and add the following to the file.

    // Bootstrap JS and CSS
    import "bootstrap";
    import "./../css/main.scss";
    // Bootstrap Popover
    import "./vendor/popover";
    // Bootstrap Tooltip
    import "./vendor/tooltip";
  10. Now that we have a file for Parcel to bundle, we need to load that file into our project. Open up _includes/shared/footer.njk we created earlier and add the following:

    <script src="./assets/main.js"></script>
  11. Open up _includes/shared/header.njk we created earlier and add the following:

    • We dynamically load the <title> and <meta name="description"> based on _data/site.json
    • We load the css via <link rel="stylesheet" href="./assets/main.css"> which will eventually be generated by Parcel.
    <!DOCTYPE html>
    <html lang="en">
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>Steve Polito Design</title>
        <meta name="description" content="" />
        <link rel="stylesheet" href="./assets/main.css" />

4. Create default layout

Now that we have everything wired up, we can create a default layout to use throughout our theme.

  1. In the root of your project, run the follow commands.

    mkdir _includes/layouts
    touch _includes/layouts/default.njk
  2. Open _includes/layouts/default.njk and add the following:

     {% include "shared/header.njk" %}
     {{ content | safe }}
     {% include "shared/footer.njk" %}
  3. Create a layout alias by running touch .eleventy.js. Open touch .eleventy.js and add the following:

    module.exports = function (eleventyConfig) {
      eleventyConfig.addLayoutAlias("default", "layouts/default.njk");
  4. Create an index page by running touch index.njk and adding the following:

    layout: default
    title: Custom Title
    description: Custom Description
    • We can write layout: default because we created a layout alias in .eleventy.js.

5. Add Production and Development npm Scripts

Now that we have all of our files created, we need to tell our project how to compile. Since Eleventy and Parcel are two separate and independent command lines tools, we can use npm-run-all to run them in parallel.

  1. Open package.json and add update the scripts section.
"scripts": {
"start": "npm-run-all --parallel dev:_",
"build": "run-s prod:_",
"dev:eleventy": "eleventy --serve",
"dev:parcel": "parcel watch ./_assets/js/main.js --out-dir ./_site/assets",
"prod:eleventy": "eleventy",
"prod:parcel": "parcel build ./_assets/js/main.js --out-dir ./_site/assets"
  • "dev:eleventy": "eleventy --serve"
  • dev:parcel": "parcel watch ./_assets/js/main.js --out-dir ./_site/assets"
    • watch ./_assets/js/main.js watches the entry point.
    • --out-dir ./_site/assets
  • "prod:eleventy": "eleventy"
    • Builds the Eleventy site.
  • "prod:parcel": "parcel build ./_assets/js/main.js --out-dir ./_site/assets"
    • Minifies scripts and styles and places them in the _site/ directory create be Eleventy.
  • "start": "npm-run-all --parallel dev:*" runs all scripts that start with dev:
  • "build": "run-s prod:*" runs all scripts that start with prod:

6. Ignore Specific Files and Folders Generated by Eleventy, Parcel and npm

  1. In the root of your project, run touch .gitignore. Open .gitignore and add the following to ignore files and folders generated by Eleventy, Parcel and npm

7. Load Test Elements on the Page To Ensure Everything Is Working Correctly

  1. Open index.njx and add the following:

    <div class="bd-example">
      <div class="p-3 mb-2 bg-primary text-white">.bg-primary</div>
      <div class="p-3 mb-2 bg-secondary text-white">.bg-secondary</div>
      <div class="p-3 mb-2 bg-success text-white">.bg-success</div>
      <div class="p-3 mb-2 bg-danger text-white">.bg-danger</div>
      <div class="p-3 mb-2 bg-warning text-dark">.bg-warning</div>
      <div class="p-3 mb-2 bg-info text-white">.bg-info</div>
      <div class="p-3 mb-2 bg-light text-dark">.bg-light</div>
      <div class="p-3 mb-2 bg-dark text-white">.bg-dark</div>
      <div class="p-3 mb-2 bg-white text-dark">.bg-white</div>
      <div class="p-3 mb-2 bg-transparent text-dark">.bg-transparent</div>
    <!-- Button trigger modal -->
      class="btn btn-primary"
      Launch demo modal
    <!-- Modal -->
      class="modal fade"
      <div class="modal-dialog" role="document">
        <div class="modal-content">
          <div class="modal-header">
            <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
              <span aria-hidden="true">&times;</span>
          <div class="modal-body">...</div>
          <div class="modal-footer">
            <button type="button" class="btn btn-secondary" data-dismiss="modal">
            <button type="button" class="btn btn-primary">Save changes</button>
      class="btn btn-lg btn-danger"
      title="Popover title"
      data-content="And here's some amazing content. It's very engaging. Right?"
      Click to toggle popover
      class="btn btn-secondary"
      title="Tooltip on top"
      Tooltip on top
      class="btn btn-secondary"
      title="Tooltip on right"
      Tooltip on right
      class="btn btn-secondary"
      title="Tooltip on bottom"
      Tooltip on bottom
      class="btn btn-secondary"
      title="Tooltip on left"
      Tooltip on left
  2. Make sure the modal, tooltips and popovers work.

    eleventy bootstrap starter themeClick to expand

Conclusion and Next Steps

Now you can override Bootstrap’s variables in _assets/css/base/_bootstrap_overrides.scss to create a more customized theme. I’ve found that by doing this and using Utilities you can create custom and unique layouts that don’t resemble Bootstrap.